Merge pull request #692 from rstudio/bugfix/tf1.13-r-custom-generator

Wrap R functions in a custom generator

Author: javierluraschi

R/model.R

@@ -934,7 +934,13 @@ as_generator.tensorflow.python.data.ops.dataset_ops.DatasetV2 <-
   as_generator.tensorflow.python.data.ops.dataset_ops.Dataset
 
 as_generator.function <- function(x) {
-  reticulate::py_iterator(function() keras_array(x()))
+  python_path <- system.file("python", package = "keras")
+  tools <- reticulate::import_from_path("kerastools", path = python_path)
+  iter <- reticulate::py_iterator(function() {
+    elem <- x()
+    reticulate::tuple(elem[1], elem[2])
+  })
+  tools$generator$iter_generator(iter)
 }
 
 as_generator.keras_preprocessing.sequence.TimeseriesGenerator <- function(x) {

inst/python/kerastools/generator.py

@@ -1,6 +1,15 @@
 
 import itertools
 
+
+def iter_generator(iter):
+  
+  def gen():
+    while 1:
+      yield iter.next()
+      
+  return gen()
+
 def dataset_generator(dataset, session):
 
   iter = dataset.make_one_shot_iterator()